X-ray CT in the detection of palm weevils

Early detection of the red palm weevils (RPW) is a major challenge in agriculture among all kinds of palm trees due to the nature of the insect and the difficulty to trace them through their life stages associated with the tree life. Many methods have been applied for the weevil detection such as X-ray diffraction techniques, fluoroscopy and ultrasound. On the other hand, the idea of tomography has been used for other purposes such as the determination of the age of the tree and for applied environmental studies. Such technology can also reveal the weevil in principle. In this study, we explore the use of X-ray CT for weevil detection with the Monte Carlo method. A model of the stem of a palm tree is developed for simulations. MCNPX is chosen to carry out the simulations for the radiography tally in the code. The tally records the 2D data of the X-ray beams irradiating the tree model. An iterative reconstruction method for cone beam CT is applied to obtain the 3D slices of the tree model. We are exploring the minimum number of projection angles and the detectability of the weevil. We shall also report the sensitivity of weevil detection using X-ray CT with a large set of simulations with different weevil sizes and tree diameters.     

Activation energy and hall-coefficient measurements in lightly dopedn-InP in the thermal freeze-out region

Summary The direct-current resistivity, β, and Hall coefficient,R _H, of lightly dopedn-type InP samples were measured at temperatures (T) down to 12K and magnetic fields up to 4.8 kG. A sharp exponential increase in β, asT was decreased, was observed for temperatures below 80 K. The Hall coefficient showed a similar trend,i.e. R _H increased sharply asT was reduced below 80 K. This is attributed to the freeze-out of conduction electrons onto their donor sites. The donor activation energy,E _d, calculated from the temperature dependence of the resistivity, was less than the theoretical prediction. An enhanced dielectric constant would be a possible candidate for such behaviour. The initial decrease in β (asT is reduced) recorded in the higher-temperature region is due to impurity scattering probably combined with lattice scattering. The authors of this paper have agreed to not receive the proofs for correction.     

Characterization of the mupirocin biosynthesis gene cluster from Pseudomonas fluorescens NCIMB 10586

The polyketide antibiotic mupirocin (pseudomonic acid) produced by Pseudomonas fluorescens NCIMB 10586 competitively inhibits bacterial isoleucyl-tRNA synthase and is useful in controlling Staphylococcus aureus, particularly methicillin-resistant Staphylococcus aureus. The 74 kb mupirocin biosynthesis cluster has been sequenced, and putative enzymatic functions of many of the open reading frames (ORFs) have been identified. The mupirocin cluster is a combination of six larger ORFs (mmpA-F), containing several domains resembling the multifunctional proteins of polyketide synthase and fatty acid synthase type I systems, and individual genes (mupA-X and macpA-E), some of which show similarity to type II systems (mupB, mupD, mupG, and mupS). Gene knockout experiments demonstrated the importance of regions in mupirocin production, and complementation of the disrupted gene confirmed that the phenotypes were not due to polar effects. A model for mupirocin biosynthesis is presented based on the sequence and biochemical evidence.     

Site-to-site peptide transport on a molecular platform using a small-molecule robotic arm

Peptides attached to a cysteine hydrazide ‘transporter module’ are transported selectively in either direction between two chemically similar sites on a molecular platform, enabled by the discovery of new operating methods for a molecular transporter that functions through ratcheting. Substrate repositioning is achieved using a small-molecule robotic arm controlled by a protonation-mediated rotary switch and attachment/release dynamic covalent chemistry. A polar solvent mixtures were found to favour Z to E isomerization of the doubly-protonated switch, transporting cargo in one direction (arbitrarily defined as ‘forward’) in up to 85% yield, while polar solvent mixtures were unexpectedly found to favour E to Z isomerization enabling transport in the reverse (‘backward’) direction in >98% yield. Transport of the substrates proceeded in a matter of hours (compared to 6 days even for simple cargoes with the original system) without the peptides at any time dissociating from the machine nor exchanging with others in the bulk. Under the new operating conditions, key intermediates of the switch are sufficiently stabilized within the macrocycle formed between switch, arm, substrate and platform that they can be identified and structurally characterized by ¹H NMR. The size of the peptide cargo has no significant effect on the rate or efficiency of transport in either direction. The new operating conditions allow detailed physical organic chemistry of the ratcheted transport mechanism to be uncovered, improve efficiency, and enable the transport of more complex cargoes than was previously possible.

Peptides are transported in either direction between chemically similar sites on a molecular platform, substrate repositioning is achieved using a cysteine hydrazide transporter module and a small-molecule robotic arm controlled by a rotary switch.     

Effect of an admixture on the electrical and thermal properties of triglycine sulphate crystals

The influence of chloroacetic acid amide (AC) on the temperature-dependence of the electrical conductivity (), thermal expansion (_ij) and specific heat ((C _p) of triglycine sulphate crystals was studied in the phase transition range (T _c=49°). The addition of isostructural AC increased the electrical conductivity, decreased the thermal expansion and changed theC _p peak. The mechanism is discussed on a thermodynamic basis.

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Zusammenfassung Der Einfluß der Zumischung von Chloressigsäureamid (AC) auf die Temperaturabhängigkeit der elektrischen Leitfähigkeit, der Wärmeausdehnung _ij und der spezifischen WärmeC _p von Triglycinsulfat-Kristallen wurde im Phasenübergangsgebiet (T _c=49 °C) untersucht. Die Beimischung von isostrukturellem AC erhöht die elektrische Leitfähigkeit und vermindert die Wärmeleitfähigkeit, während derC _p-Peak verändert wird. Der Mechanismus kann thermodynamisch diskutiert werden.

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(), () _ij) () , T _c=49°. , , , , C _p. .

     

Thermodynamic studies on the ferroelectric phase transition in neutron irradiated (LixK1−x)2SO4 crystals at high temperature

Thermodynamic studies of (Li_xK_1?x)₂SO₄, LKS, mixed crystals have been made in the concentration range (x=0.1, 0.2, ...,x=0.5). The thermal behaviour has been investigated by differential thermal analysis, DTA, and differential scanning calorimeter, DSC, in the vicinity of high temperature phases. Also, the effect of the thermal neutron irradiations on the thermal properties of mixed crystals was studied. The results showed a change in the transition temperatureT _c, as well as the value of specific heatC _p at transition temperature, due to the change of stoichiometric ratio and radiation doses. The change of enthalpy and entropy of mixed crystals have been estimated numerically.     

Numerical solution for a sub-diffusion equation with a smooth kernel

In this paper we study the numerical solution of an initial value problem of a sub-diffusion type. For the time discretization we apply the discontinuous Galerkin method and we use continuous piecewise finite elements for the space discretization. Optimal order convergence rates of our numerical solution have been shown. We compare our theoretical error bounds with the results of numerical computations. We also present some numerical results showing the super-convergence rates of the proposed method.     

Convergence and superconvergence analyses of HDG methods for time fractional diffusion problems

We study the hybridizable discontinuous Galerkin (HDG) method for the spatial discretization of time fractional diffusion models with Caputo derivative of order 0 < α < 1. For each time t ∈ [0, T], when the HDG approximations are taken to be piecewise polynomials of degree k ≥ 0 on the spatial domain Ω, the approximations to the exact solution u in the L _∞(0, T; L ₂(Ω))-norm and to ?u in the \(L_{\infty }(0, \textit {T}; \mathbf {L}_{2}({\Omega }))\)-norm are proven to converge with the rate h ^k+1 provided that u is sufficiently regular, where h is the maximum diameter of the elements of the mesh. Moreover, for k ≥ 1, we obtain a superconvergence result which allows us to compute, in an elementwise manner, a new approximation for u converging with a rate h ^k+2 (ignoring the logarithmic factor), for quasi-uniform spatial meshes. Numerical experiments validating the theoretical results are displayed.     

Multiplicative linear search for a brownian target motion

This paper investigates a search problem for a brownian target motion on one of n-intersected real lines in which any information of the target position is not available to the searchers all the time. We have n-searchers start searching for the target from the origin that is the intersection point of these lines. Each of the searchers moves continuously along his line in both directions of the starting point. The purpose of this paper is to formulate a search model and find the condition under which the expected value of the first meeting time between one of the searchers and the target is finite. Also, we show the existence of the optimal search plan which minimizes the expected value of the first meeting time and find it.     

Swarm intelligence-based hyper-heuristic for the vehicle routing problem with prioritized customers

The vehicle routing problem (VRP) is a combinatorial optimization management problem that seeks the optimal set of routes traversed by a vehicle to deliver products to customers. A recognized problem in this domain is to serve ‘prioritized’ customers in the shortest possible time where customers with known demands are supplied by one or several depots. This problem is known as the Vehicle Routing with Prioritized Customers (VRPC). The purpose of this work is to present and compare two artificial intelligence-based novel methods that minimize the traveling distance of vehicles when moving cargo to prioritized customers. Various studies have been conducted regarding this topic; nevertheless, up to now, few studies used the Cuckoo Search-based hyper-heuristic. This paper modifies a classical mathematical model that represents the VRPC, implements and tests an evolutionary Cuckoo Search-based hyper-heuristic, and then compares the results with those of our proposed modified version of the Clarke Wright (CW) algorithm. In this modified version, the CW algorithm serves all customers per their preassigned priorities while covering the needed working hours. The results indicate that the solution selected by the Cuckoo Search-based hyper-heuristic outperformed the modified Clarke Wright algorithm while taking into consideration the customers’ priority and demands and the vehicle capacity.